Hariliku siili elupaikade sidusus Tallinna linna Nõmme ja Mustamäe linnaosades

Suik, Karina (2020) Hariliku siili elupaikade sidusus Tallinna linna Nõmme ja Mustamäe linnaosades. [thesis] [en] Habitat Connectivity of the European Hedgehog in Nõmme and Mustamäe Districts in the City of Tallinn.

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Abstract

Alates 19. sajandi keskpaigast on linnad pidevalt kasvanud, mille tulemusena on looduslik maastik tundmatuseni muutunud ning paljud elupaigad hävinud. Tänapäeval eelistatakse uusarendusi ehitada looduslikele aladele, mis tähendab, et parkide, aedade ja muude rohealade rohkus väheneb linnades üha enam. Linnapiirkondade bioloogilist mitmekesisust ohustabki põhiliselt elupaikade killustumine, mille põhjustajaks on sõiduteed ning arendustööd. Killustumise tulemusena tekivad linnades isoleeritud populatsioonid, kus võivad ajaga liigid välja surra. Linnaloodusele on aga ülimalt oluline, et tööstuslikud ja looduslikud alad moodustaksid omavahel niinimetatud rohelise infrastruktuuri, mis oleks positiivne nii inimestele kui ka loomaliikidele. Samas võib linnakeskkond pakkuda mõnele liigile paremaid elutingimusi kui maapiirkonnad, näiteks võivad koduhoovid pakkuda väikeloomadele mikroelupaiku ja toiduallikaid. Tallinn on bioloogiliselt väga mitmekesine linn, mis tuleneb sellest et asub Läänemere rannikul. Linnas on tänu Nõukogude perioodi piirangutele säilinud mitmed looduskeskkonnad, mille tulemusena võib seal kohata mujal Euroopas haruldaseks jäänud looma- ja linnuliike. Tallinna linnaosad on väga eriilmelised, kui Nõmme ja Pirita koosnevad pigem erahoovides ja puistutest, siis Mustamäe ja Lasnamäe on suuresti kaetud tööstuslike alade ja kortermajadega. Uuringuobjektiks olnud harilik siil on öise eluviisiga putuktoiduline loom, kelle kodupiirkond võib jääda 10 kuni 40 hektari vahele. Siilid eelistavad oma elupaigana võsastunud aedasid, metsi ja parke. Linnades ohustavad harilikku siili põhiliselt sõiduteed, mida nad tihtipeale keelduvad ületamast, selle tulemusena on nende elupaigad killustunud. Mudeli modelleerimise tulemusena selgus, et hariliku siili elupaigad on Nõmme linnaosas üldiselt hea sidususega. Põhiliselt erahoovidest ja puittaimestikuga maakattest koosnevas linnaosas on elupaikade vahel piisavalt kitsad teed, et loomad on võimelised neid ületama. Erinevalt Nõmmest on Mustamäel siilide elupaigad killustunud ning isenditel ei ole võimalik ühest elupaigast teise liikuda. Mustamäe elupaikade sidususe modelleerimist võis mõjutada vaatlusandmete puudumine potentsiaalsetes elupaikades. Kahjuks ei ole aga teada, kas Mustamäel esinebki harilikku siili vähe või on vaatlusandmed lihtsalt puudulikud. Seega tuleks tulevikus kaardistada, kas ja kus harilikku siili Mustamäel esineb. Hariliku siili elupaikade sidususe parandamiseks tuleks Tallinna linnaosades arendada rohelist infrastruktuuri, kus liigi elupaigad on paremini ühendatud ja isendid saavad nende vahel kergelt liikuda. Samuti tuleks mõlemas linnaosas muuta praegused lage alad ja rohumaad metsikumaks, mis tekitaks siilidele juurde uusi elupaiku.

Abstract [en]

The following graduation thesis Habitat Connectivity of the European Hedgehog in Nõmme and Mustamäe Districts in the City of Tallinn aims to give a short overview of the positive and negative impacts of urbanization, the biodiversity in the city of Tallinn and European hedgehogs. The main output of the thesis is a habitat dispersion map of European hedgehog in Nõmme and Mustamäe districts, which is followed up with an analysis and recommendations to improve the habitat connectivity. The ever-expanding cities and the accompanying changes in the landscape often lead to loss of biodiversity and destruction of habitats of many species, including hedgehogs. Biodiversity in urban areas is largely threatened by habitat fragmentation caused by roads and development work. Fragmentation leads to isolated populations and this could cause the extinction of some species in cities. This means it is extremely important to develop a so-called green infrastructure in cities, which connects industrial and green areas in cities in a way that benefits both humans and animal species. Tallinn is a biologically diverse city due to its location on the coast of the Baltic Sea and the Soviet period restrictions. However, the districts of Tallinn are very diverse, while Nõmme and Pirita consist of parks, private houses and gardens and woodlands, then Lasnamäe and Mustamäe are largely covered with industrial areas and apartment buildings. European hedgehog is a nocturnal insectivorous animal, whose home area can be between 10 and 40 hectares. Hedgehogs prefer overgrown gardens, forests and parks as their habitats. In cities, hedgehogs are mainly threatened by roads, which they often refuse to cross, resulting in fragmented habitats. As a result of the modelled habitat dispersal map, it became clear that the habitats in Nõmme district are generally well connected and hedgehogs are able to move from one habitat to another without major obstacles. In a district made up mainly of private gardens and woodlands, the roads between the habitats are narrow enough for the animals to be able to cross them. By contrast, the habitats of Mustamäe are very fragmented and it is not possible for hedgehogs to move from one habitat to another. The habitat connectivity modeling at Mustamäe may have been influenced by the lack of observational data in potential habitats. Unfortunately, it is not known if the data is simply incomplete or whether there are only a few hedgehogs in the area. Therefore, this is a topic to be researched in the future. In order to improve the connectivity of the European hedgehog habitats, green infrastructure should be developed in the two studied districts, so that the species can move from one habitat to another without big obstacles. In addition, the current open areas and grasslands should also be made “wilder”, which means planting and growing denser shrubs and woody vegetation in these areas. Such activities could provide new habitats for hedgehogs and other animal and bird species. The main aim of the graduation thesis has been reached. The author suggests that the same methodology could be implemented to map out the entire city of Tallinn’s European hedgehog and other animal species’ habitat connectivity.

Item Type: thesis
Advisor: Oliver Kalda
Subjects: Environmental Technology > Environmental Protection > Estonian Biota and Biocenosis
Divisions: Institute of Technology and Circular Economy > Environmental Technology and Management
Depositing User: Karina Suik
Date Deposited: 04 Jun 2020 10:25
Last Modified: 04 Jun 2020 10:25
URI: https://eprints.tktk.ee/id/eprint/5271

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